> Shortly after humans arrived, however, Genyornis went extinct. The birds are thought to have been eaten into extinction, with climate change hastening their demise.
It’s funny how they (and all the other large mammals) survived for 1.8M years of massive global climate change but the period just after we arrived (like in the Americas) was what “hastened their demise” rather than the humans with clubs they hadn’t had time to evolve to be scared of, eating every last one of them.
> The paper suggests that these adaptations might be a sign that the bird was already struggling before the arrival of humans. Changing climate patterns meant that wet areas like Lake Callabonna started getting drier around 60,000 years ago and dried up completely 12,000 years later.
> There are indications that the legs of Genyornis were gradually adapting to this drier climate, but the species would have remained under considerable pressure. This environmental stress is thought to be why the birds had higher than expected levels of bone disease at around the same time.
In this case it sounds like climate change was in fact a stressor, though I believe you're right--even without climate change this bird would have gone the way of the moa. Perhaps a better phrasing would have been "Already under stress from climate change, they are thought to have been eaten to extinction."
Disagree with this assessment. There was not large numbers of humans until the end of the glacial period and the advent of pastoralism and agriculture.
@helpfulContrib - I can't reply your message directly.
I'm not trying to deny anything. I'm sure there were pockets of what we (modern) might recognise as agriculture, though not pastoralism (for obvious reasons).
My question was actually just what it looked like, an earnest question to chrisco255, replying to elmomie, about the context of their statements.
GP seemed to be talking global, and so did parent - which would make sense in the context of climate change (a global phenomenon) and also massive human population growth (also mostly global, resulting form settlements / agriculture).
Most estimates put the total global human population at less than 1 million prior to the end of the glacial period and the beginning of the Holocene.
For most of the globe agriculture was not possible. While canines were probably domesticated in the glacial period, they served as hunting partners primarily. It's actually quite hard to build fencing over large amounts of land area (like sheep and cows require) that is capable of keeping animals in, unless you have metal to cut wood with. The United States had open cattle ranging until barbed wire was invented in the 1870s, since it was too difficult to fence. And open ranging was only possible after horse domestication.
We also do not see evidence of grain domestication or any kind of real farming until the start of the Holocene 10K-12K years ago. The climate was not particularly friendly to farming, and without access to metal, farming is orders of magnitude more difficult.
The original article is about Australia alone, and 45K years ago, Australia probably had a human population in the low thousands, with it being on the frontier of human expansion at the time. There is no evidence of massive human population at that time or any time before 12K years ago. In fact, there's several population bottlenecks where they think the total number of humans alive globally was around a few thousand.
This is good - in that it aligns with my understanding (though my knowledge was not that detailed on timeline, context, and figures - thank you for those).
I know living, brush, or ha-ha type fences would have been possible - but agree all of those were easier with some metal utensils.
For one species, sure, for 35 you have to wonder how ideologically driven you have to be to keep blaming the environment. We're at tobacco companies in the 90s level of denialism here.
This is an uncharitable interpretation of the facts.
The thing about climate change in prehistory is that it drives changes to human life. Archaeologists put glacial maxima on their timelines because it's such an important factor when trying to understanding human migration, the spread of new technologies that do better in drier or wetter climates, the shift to different food sources, and so on. This predates the current climate-aware political landscape.
If 90% of a species is killed off by climate change, and if for hundreds of thousands of years that species survived glacial maxima in reservoir populations in areas that are now populated by starving humans who kill the remaining 10%, was it the climate or the humans who wiped out the species? The changing climate killed more, but the humans were the differentiating factor, so which one do you point the finger at?
> The changing climate killed more, but the humans were the differentiating factor, so which one do you point the finger at?
If we're the differentiating factor, I'd have to blame us. Am I right in understanding that these species were normally being thinned during each glacial maxima, such that it was already a set part of their evolutionary environment? If that's right, then aren't we the ones to blame?
Otherwise, is a murderer merely a "contributing cause" to someone's death if the victim happens to be sick at the time of the killing?
I think there's a good argument that either or both factors contributed. We tend to blame people because they have agency and the natural world does not, and that's not a bad way to understand things.
My main point was that I don't think it would be denialism for someone to say "no, the species was pushed to the brink by climate change anyway, we know other species went extinct prior to human colonisation, and even though humans arguably made it worse there's no conclusive evidence". Glacial maxima are hundreds of thousands of years apart and given the timescales involved it's hard to say whether a species is adapted to them or whether it just got lucky.
Weren't there something like 5 glacial maxima in the past 200 thousand years? I had the impression they were more regularly occurring than "hundreds of thouands of years apart".
Yeah my bad, I meant that glacial and interglacial periods happen in a cycle that can take up to 100k years before it repeats, but phrased it in a way that's outright wrong as well as misleading. I think the overall point still stands though.
I’m not disagreeing with the premise of what you are saying but did you read the article? At least with this I don’t think anyone was saying it was the British that made it go extinct. The article references a study saying about the native people eating the eggs like 50,000 years ago.
I think the suggestion is that the flora ~80,000 ya did not need fire so much as it does today, and that the change in fire requirement was a result of broad-scale, regular, frequent, intentionally lit fires.
Adaptation and species selection has resulted in what we have now -- as distinct from finding ourselves in a land that happens to need regular burning.
Contrast us with comparable latitudes (15-35 from the equator) on other landmasses.
In Brazil, transpiration from the Amazon rainforest produces more water vapour than the amount of water transported by the Amazon river. This is known as an atmospheric river (e.g. [1]) and is now seen as critical to the Brazilian climate. I think the theory is that wide spread burning in Australia destroyed the atmospheric river there, which led to a much drier continent than existed before humans arrived.
There's a lot of divided opinion there in the informed community, not many think that humans soley wiped out the megafauna, a good number question whether they played a significant decisive role in their demise, most think humans killed and ate a few.
What is certain is the same change in global conditions that allowed humans to walk to Australia and later filled the moat coincided with the fall off in megafauna. There's correlation, but causation??
It turns out humans coexisted with the megafauna over about 80% of south-eastern Sahul for up to 15,000 years, depending on the region in question.
In other regions such as Tasmania, there was no such coexistence. This rules out humans as a likely driver of megafauna extinction in those areas.
> The first people probably came to Australia from around the area that is now Timor. To get to Australia, they must have made a canoe voyage of about 90 to 150 kilometres of open water, which would have been a remarkable maritime achievement
> humans with clubs they hadn’t had time to evolve to be scared of
This is not a thing. Species don't require generations to learn to be afraid of other species that hunt them. Species have encountered new species since the beginning of time. If it took 1000 generations to learn such a thing, nothing would have ever made it.
It's not as if there's a shortage of dangerous predators in Australia, even to this day.
Just because an article hand waves an explanation doesn't make it so.
We have actual evidence that it is a developed instinct. If you’ve ever been to the Galapagos islands, it’s extremely obvious. The sea lions and pelicans casually walk up to the counter at the fish market as if they’re just regulars shopping.
It takes surprisingly few generations to evolve traits. If there is a distribution of skittishness and a high pass filter takes away everything under a given limit, you'll get rapid evolution.
As another example, urban populations of animals have evolved to tolerate noise in the span of very few generations.
Searching "giga-goose" before June 3rd brings up basically nothing, someone last year called this species a "gigantic goose" and a bunch of unrelated things. I wonder where the nickname came from, and how important it was towards getting this article published.
Also I wonder if there's a move away from "mega" towards "giga" as mega anything seems kinda small. I can't see "tera" ever being a thing, I can't think of an independent connection to some other word meaning large.
Etymologically, “giga” does make more sense as a generic ’big’ prefix than “mega”. I believe that the former basically means “great” while the latter means “mighty”, which is less flexible.
“Tera” has the problem of being overloaded. It’s a homophone with “terra” which is a common prefix for things related to the Earth or ground. Also that lack of a strong second consonant hurts it. Etymologically it means “monstrous”, which is even less flexible.
I'm generally curious about what these ancient megafauna tasted like. Especially this one now, seeing as humans apparently ate them to extinction. Someone start cloning monster geese!
Local legend in Central America has it that manatees contain every kind of meat – chicken, beef, poultry, even bacon. As you can imagine, before modern protections, manatees tended to disappear not long after humans moved into a region.
They spared no expense rendering that image to show it in a friendly park setting, granted, an AI video clip of it learning to open doors would have been much more menacing.
It’s funny how they (and all the other large mammals) survived for 1.8M years of massive global climate change but the period just after we arrived (like in the Americas) was what “hastened their demise” rather than the humans with clubs they hadn’t had time to evolve to be scared of, eating every last one of them.